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April 13, 2012

Could Tornado Alley Be Extended?

by editor

A research firm is looking to broaden the borders of a strip of the Midwest known as Tornado Alley. Tornado Alley has traditionally included the Plains states from the Dakotas to Texas. CoreLogic, a Californian risk and management company has studied weather data from across the country and is now suggesting this region should be stretched as far east as western Ohio, as well as covering a majority of the deep south.

According to a report from the National Oceanic and Atmospheric Association (NOAA), tornados and the storms responsible for producing them account for 57% of insured catastrophic losses each year, and according to new data, these storms are increasing in frequency every year.

Some states are beginning to see more of these storms where once they were quite rare, such as Iowa and Mississippi.

According to CoreLogic´s new research, Iowa is at a “very high” or “extreme” risk of tornados. Iowa´s western half is listed to have an “extreme” risk.

Part of what´s driving this new boundary-extending suggestion is tornado data from the past 20 years. In that time, states normally outside of tornado alley, such as Florida, Iowa, Louisiana, and Mississippi have had more tornados on record than traditional tornado alley states.

Last year´s highly active and destructive tornado season prompted CoreLogic to conduct this research. According to them, the outbreak in the Southeast in April of last year was the most expensive tornado outbreak ever recorded, resulting in 321 deaths and $7.3 billion in insured losses.

“The inland South has experienced rapid (economic) growth in the past 20 to 30 years,” says Howard Botts of CoreLogic, according to USA Today reporter Doyle Rice. Botts also noted the majority of foreign car makers now have factories in the high risk areas of the South.

“The apparent increase in the number of incidents and shift in geographic distribution of losses “¦ last year in the US called the long-held notion of risk concentration in Tornado Alley into question,” Botts says.

While experts hailed many of last year´s severe weather events outside of the plains as anomalies, Botts said they should have been viewed as typical.

The risk for tornados now extends to much of the eastern half of America and, according to Botts, at least 26 states have some sort of risk for these severe storms.

So, rather than refer to the region at high risk for tornados as “Tornado Alley,” meteorologist Grady Dixon of Mississippi State University suggests another name: Dixie Alley.

According to USA Today, Dixon also conducted a similar study last year and found his results agreed with CoreLogic´s, though not all experts have been able to do the same.

Harold Brooks is a research meteorologist at the National Sever Storms Laboratory in Norman, Oklahoma and says the storms outside of Tornado Alley have been noted and discussed before.

“If the report is trying to identify where the most tornadoes are, then it´s broader than the Plains, and we´ve known that for decades,” said Brooks. Brooks also says Tornado Alley is still very active, noting, “There aren´t very many down years in the Plains.”

Greg Carbin, warning coordination meteorologist with the Storm Prediction Center in Norman, Oklahoma agrees with Brooks, saying CoreLogic´s research is based on problematic data.

“With respect to significant (EF2 and stronger) tornadoes, there is no statistically significant trend in these tornadoes, the ones that pose the greatest threat to life and property,” Carbin says.